Conventional generator sets have found a wide variety of uses. Typically, a generator set comprises and engine in association with a generator or generator mechanism, used to provide electrical power. Such systems are used, for example, to provide emergency power in homes and offices. Portable units are used to provide electrical power at work stations in the field and for recreational vehicles and the like.
Generally, the engine is spark-ignited, utilizing gasoline, natural gas, propane, diesel, or similar fuel. The engine is typically set to run at a preferred speed, usually defined in terms of the revolutions per minute (rpm) of the engine driveshaft. This speed is ordinarily determined by the rate at which the engaged generator must be driven, to efficiently produce power during a typical load.
During use, the load on the engine may vary considerably. This may occur as power drain on the generator is varied. For example, a load variation will occur as a power tool or appliance is turned on or off.
If a heavier load is placed on the engine, the engine will tend to slow down. The engine governor system or mechanism provides for a continual adjustment in engine speed in response to the load variations, to maintain a relatively constant engine speed. Generally this is accomplished through an adjustment in a throttle of the engine, i.e. air or fuel flow from or through the carburetor. Typically this is accomplished through adjustment of a butterfly valve or throttle plate. That is, should a greater load be placed on the engine, the throttle is adjusted somewhat in response to the concomitant decrease in rpm, allowing the engine to speed up. On the other hand, should a load suddenly be taken off an engine, the throttle is adjusted in an opposite manner, in response to the rpm surge, to slow the engine down.
The typical governor system includes a sensor mechanism which detects, either directly or indirectly, the rotation speed of the engine driveshaft or crank shaft. Through conventional governor linkage mechanisms including a governor member, the sensor typically communicates with a throttle control. A typical governor linkage mechanism includes a governor arm, as a governor member. The governor arm is linked to another governor member, a governor rod, which provides mechanical communication with the throttle control. In many conventional systems this occurs through mechanical connection to a pivotable rod on which a throttle plate is mounted. Rotation of the pivotable rod selectively orients the throttle plate to increase or decrease engine speed.
Such systems are well-known and will not be described in detail herein. However, generally, should the engine speed change, the governor sensor, in response to the change in engine speed, moves the governor member. Movement of the governor member typically causes controlled adjustment of the throttle, generally through a predicted pivoting of the throttle plate to adjust the engine speed back toward a desired norm.
Since the very earliest developments of governor systems, there have been problems of hunting or searching and over-compensation. That is, while attempting to return the engine speed to the normal, desired, speed, the governor usually over-compensates. As a result, the engine may speed up and slow down a number of times, before it finds the correct speed. This is typically referred to as "hunting" or "searching".
Searching is a problem, since it may lead to undesired power fluctuations and inefficient utilization of fuel. In the past, attempts to control hunting or searching have generally involved efforts to reduce to a minimum the amount of mechanical friction present in the governor linkage mechanism. This has generally led to an improvement in governor performance, partially due to a limitation in the amount that any given movable mechanical joint can unpredictably "stick". However, even reduced friction systems still undergo a substantial amount of undesired searching or hunting.
What has been needed has been a system and method for the reduction and/or control of undesired over-compensation leading to hunting or searching.